A wealth of empirical ecology has established the importance of individual adaptive behavior—e.g., tradeoffs between feeding and risk in foraging—on community and ecosystem ecology, and the importance of feedbacks from higher levels to the individual—e.g., competition for resources that affect adaptive foraging behavior. Now that we recognize that adaptive behavior and feedbacks are ubiquitous and essential, is ecological theory still relevant? Traditionally, population and ecosystem theory ignore individuals and the effects of behavior, and behavioral ecology focusses on isolated individuals that are not subject to the feedbacks from the population or community. Do we have theory that considers multiple ecological levels, from individuals to communities and ecosystems? Is theory useful for including behavior and feedbacks in practical models of real systems? Is such theory testable, and does it provide a useful framework for empirical research? This symposium will present examples of theoretical models that explicitly address multiple levels of real ecosystems. Examples will include (a) community and ecosystem models that represent adaptive behavior of individual organisms and the effects of those behaviors on trophic dynamics and (2) theory for individual adaptive behavior that works for populations and communities of adapting individuals when the options and resources available to each individual are affected by feedbacks from the behavior of other individuals. The primary approach explored is “individual-based ecology”: not just the use of individual-based models but also the development and testing of theory for adaptive behavior in a way that explicitly considers higher levels. A key element of the approach is “pattern-oriented theory development,” a strategy for (a) posing alternative hypotheses for how individuals make adaptive decisions, (b) testing and falsifying those hypotheses against observations made at individual- and higher levels of organization, and (c) devising empirical research to further refine the theory. To bridge from examples to useful lessons, the symposium will conclude with a synthesis presentation and discussion focused on how theory that considers multiple ecological levels can be used in practical models for managing and understanding real ecosystems. The synthesis will also consider the traditional gap between theoretical and empirical ecology and how it can be bridged by theory that explicitly considers links between individuals and higher levels of organization.